Recording device



March 8, 1960 5. 1... SOLAR RECORDING uavxcz:

Filed Oct. 18. 1957 O 0 O 0 0 O O O 0 0 6 0 0 9,0 0 0 0 0 o INVENTOR. JAMl/H 1. SOLAR AGENT United States Patent RECORDING DEVICE Samuel L. Solar, San Jose, Calif., assignor to International Business Machines Corporation, New York, N.Y., a

corporation of New York 7 Application October 18, 1957, Serial No. 691,087

1 Claim. (Cl. 346- -21) This invention pertains to a cyclic informatior'i-displaydevice and more particularly to an information display device for recording and cyclically displaying transitory information thereon.

Accordingto the present invention, an extremely simplified recording .and display mechanism, has been provided which is suitable for displaying transitory information of current interest but which information usually requires no permanent record thereof, such as found in recording certain business messages, transactions and inmatrix fashion, substantially as shown in U.S. Letters Patent 2,457,133. An erasing station is also provided comprising electrodes of an opposite polarity whereby characters recorded, as above, are erased by reversing the acid or alkaline condition of the impregnant.

Accordingly, it is an object of this invention to provide a printing device for erasable recording of information upon a cyclic recording medium.

It is another object of this invention, for reasons of economy, to provide an electrolytic recording mechanism requiring no supplyof paper to be continually replenished.

It is another object of this invention to provide a recording mechanism for recording and erasing on a cyclic carrier using a reversible electro-chemical reaction.

Other objects of the invention will be pointed out in the following description and claim and illustrated in the accompanying drawing which discloses, by way of example, the principle of the invention and the best mode which has been contemplated of applying that principle.

The single figure of the drawing is a perspective view of a cyclic information display device according to the invention herein.

The principle of operation of the present invention resides generally in the fact that when any neutral, mildly acid, or mildly alkaline electrolyte is subjected to an electric current, acidification is brought about at the positive electrode while the electrolyte is made alkaline at the negative electrode. .A suitable acid-base indicator capable of giving a color change responsive to either an acid or alkaline condition of the electrolyte is added to it. In this manner, the electrolyte can be dyed a predetermined color, dependent upon the indicator used and the polarity of an applied current.

For example, to illustrate the principle, if a piece of I filter paper is soaked with a neutral aqueous solution of sodium sulfate (M1 80 (electrolyte) containing a small amount of phenolphthalein (acid-base indicator), the

resulting color of the paper will be white since the neutral solution is clear. If the leads from a battery are pressed howeverga strong fabric having good moisture retention qualities, such as linen, is preferred. Belt 1 is impregnated with a solution of electrolyte and an acid-base indicator. The preferred indicator used happens to be responsive to alkalinity; therefore, writing is done by a cathode and erasing by an anode. However, indicators providing a color change'under acid conditions may, obviously, be used in a similar manner, with writing being done by anodes and erasing by cathodes.

The indicator preferred for use in actual practice produces a very dark purple color providing excellent contrast. It is comprised of a mixture of 4 grams of anhya drous sodium sulfate (Na SO and milligrams of each of the following ingredients, the mixture being Meta-Cresol Purple Cresol Red Alpha naphthol benzein If it is desired, 100 milligrams of Cetylpyridiniurn Chloride can be added as a preservative.

An indicator solution 6, such as described above, is placed in a tray 8 through which belt 1 is drawn via rollers 9, 10, 11 and 12 as feed sprocket roller 2 is rotated counter-clockwise. As belt 1 leaves tray 8, having been immersed in solution 6, excess liquid is removed therefrom by passing it between roller 12 and a squeegee 13.

Belt 1 passes around a guide 15 and onto an anode 16 connected to the positive side of a battery 18. Anode 16 serves to support belt 1 during its upper travel. Belt 1 is fed between anode 16 and a plurality of cathode probes 17 (shown schematically in the drawing). Each of probes 17 is connected to the negative side of battery 18 via a separate switch 19. In this manner the selective closing of switches 19 for various durations will produce human readable characters upon belt 1 by imparting an alkaline condition to the outer surface of belt 1 in the region of probes 19 as they are negatively charged. As shown in the drawing, the letters S, E, L have been written, the bottom of the letter L being in the process of completion, as shown (explaining why the nearest of switches 19 is still closed).

Belt 1 continues its counter-clockwise travel, passing over roller 2 and around another guide 21 to an erase station 22. Station 22 is arranged to reverse the pH of the impregnant sufficiently on the outer surface of belt 1 to change the condition created by probes 19, and in this manner erase the printing as explained above. For this purpose, station 22 is comprised of a battery 28 connected to an anode 26 contacting the writing surface of belt 1 and a cathode 27 (in the form of a roller) located on the opposite side of belt 1. Cathode 27 is connected to the negative side of battery 28 via a switch 29 for controlling erasing at station 22. By suitably coordinating switches 19 with erasing switch 29, some parts of the printing on belt 1 can be displayed repetitiously while others are erased.

From station 22, belt 1 is guided beneath a guide plate Patented Mar. 8, 1960 31 into tray 8 for re-impregnating it with solution 6. From here another printing cycle is begun.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to the preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilledv in the art, without departing from the spirit of the invention. 'It is the intention, therefore, to be limited only as indicated by the scope of the following claim.

What is claimed is:

A cylic information display device comprising an endless linen belt, a plurality of guides supporting said belt, said guides defining a closed cyclic path, means for driving said belt continuously along said path, said driving means including both a line of holes in and along said belt and a coacting feed sprocket roller having a plurality .of pins extending outwardly therefrom for engaging said holes to drive said belt, an acid-base indicator bath' in said path for impregnating said belt, said bath including :an aqueous solution of anhydrous sodium sulfate, Meta- Cresol Purple, Cresol Red, Alpha Naphthol Benzein and Cetylpyridinium Chloride, said guides being further arranged to pass said belt through said bath, a squeegee in contact with and disposed across said belt and placed to remove excess quantities of said bath from said belt as said belt leaves said bath, said belt having an inner and an outer surface thereto, an information recording circuit in said path including a first direct current voltage source, a smooth electrically conductive anode member supporting said belt through a portion of said path, said anode member being connected to the positive side of said first voltage source and in surface contact with said inner side, a plurality of cathode probes connected in parallel to the negative side of said first voltage source and positioned in contact with said outer surface, means for energizing each of said probes independently and selectively to visibly develop contrasting characters on said outer surface responsive to various selectively energized combinations of said probes, an erasing circuit in said path including a second direct current voltage source, an elongated smooth anode and cathode disposed to extend across said belt in close spaced apart relation, said belt passing therebetween, said anode being in contact with said outer surface and connected to the positive side of said second voltage source, and said cathode being in contact with said inner surface and connected to the negative side of said second voltage source to provide an electrical circuit through said belt, said erasing circuit further including means for selectively interrupting the flow of current therethrough to allow information recorded by said probes to remain visible on said belt for one or more cycles of operation as desired. A

References Cited in the file of this patent UNITED STATES PATENTS 

